How can metabolic surgery cure diabetes so fast?

No-one can explain this strange phenomenon. The majority of type 2 diabetics who undergo metabolic surgery recover from diabetes only a few days after the procedure, long before any weight loss has occurred. Now researchers at Lund University Diabetes Center plan to find out what is happening by studying both patients and pigs before and after metabolic surgery.

"Since the recovery from diabetes occurs so early, a process other than weight loss has to be behind it. If we can identify and imitate this process, it could lead to entirely new ways of treating type 2 diabetes", says Nils Wierup, one of the researchers behind the study.

There is a strong correlation between being overweight or obese and type 2 diabetes, and many diabetics can recover if they lose weight, but this is not the focus of the study. Instead, the focus is on a side effect - the astonishingly fast normalisation of the glucose homeostasis which is seen in 85 per cent of diabetics after metabolic surgery.

Gastric bypass surgery means rerouting food content directly to the small intestine, bypassing the stomach. This means that portion sizes have to become smaller and weight loss in the long term becomes significant.

"We don't mean that everyone with type 2 diabetes should undergo surgery, but maybe we can learn to achieve the same anti-diabetic effect without the surgery", says Nils Wierup.

Patients who will be invited to participate in the study are type 2 diabetics who are going to have gastric bypass surgery. They will undergo a variety of tests both before and periodically after the surgery.

The research team will also use pigs, both healthy and diabetic, for experiments that cannot be performed on patients.

"Pigs are suitable because they resemble humans in many ways, including anatomically and in terms of gastrointestinal hormones", says Nils Wierup, adding that it is possible that a less extensive gastric bypass may have the same dramatic effects.
"In that case the area we need to search will be smaller, and the mechanism we are searching for will be easier to find."

On the list of suspected factors are changes in the effects of gastrointestinal hormones. It is known that hormone secretion from the gastrointestinal tract plays an important role in glucose homeostasis. Gastric bypass surgery changes the conditions. Metabolic surgery might also drastically change the gastrointestinal bacterial flora since the pH changes, and this should mean that other species of bacteria can establish themselves.

"But it could also be a completely different mechanism. We have to look at a great variety of possible factors", says Hindrik Mulder, one of the researchers on the team.